OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 4 No. 4 2022 Fig. 5. Dynamics of friction coefficients values of a pair: bronze (9 % Al; 2 % Mn) and polymeric material during the completion of the running-in process Fig. 6. Dynamics of friction coefficients values of a pair: titanium alloy VT-3 and polymeric material during the completion of the running-in process In turn, the nature of the running-in process of the metal-polymer friction pair, which largely determines the further life of the working unit of the mechanism, depends on the hardest surface grade of finish [24, 25]. To study the influence of this factor (roughness) on the tribotechnical properties of the metal-polymer pair, bronze (9 % Al; 2 % Mn) and Maslyanit 12, the wearless properties of which were of particular interest for further studies, were selected. Bronze counterbodies were made with five different grades of surface finish. Each test was performed according to the above procedure for one hour. The test results are presented in Table 2 and shown graphically (Figure 7–9). Water, including sea one, which negatively affects the friction of metal pairs, favorably affects the friction process of Maslyanites. This is explained by the hydrodynamic effect that occurs in the contact zone in addition to separation oxide film mentioned above. It should be noted that in units with frequent stops or with the possibility of abrasive getting into it, friction occurs with permanent running-in. This is due to the transition of hydrodynamic friction to boundary friction, which wear is 3–4 times higher than in liquid friction [23]. The graphs of the effect of counterbody surface roughness on hourly mean wear and wear per kilometer of slip path traveled (Figure 7 and 8) are identical and tend to reduce wear as the roughness of the metal surface decreases.
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